Electrical devices, such as electrical medical devices, may incorporate a battery power supply to enable them to be used without the limitations of a power cable.
Many such electrical devices may be used in environments where they may come into contact with liquid. For example, electrical medical device for in vivo use may be used in environments where they come into contact with bodily fluids and electrical medical devices which include reusable portions requiring decontamination between uses may be used in environments where they come into contact with cleaning products.
It is often necessary for such electrical devices to be sealed against penetration by liquid to prevent damage to the device or loss of battery power.
A secondary concern is to avoid gaps leading to spaces where microbes can proliferate, and which can be prove difficult to clean.
Many known electrical devices powered by removable batteries comprise a battery compartment, having a cover, into which one or more removable batteries may be mounted. When inserting or removing batteries from the battery compartment it is necessary to remove and/or reattach the cover. Therefore, it is difficult to maintain a high quality seal between the cover and the remainder of the electrical device. In addition, the quality of the seal may deteriorate further each time that the seal is broken.
It is known to provide electrical devices containing rechargeable batteries which remain sealed within the device. However, the maximum capacity (in usable ampere hours) of the rechargeable batteries decreases with repetitive use. Furthermore, it is not possible to carry out some decontamination procedure (e.g. autoclaving, irradiation) on electrical device from which batteries cannot be removed.
Thus, the aim of some aspects of the invention is to provide an electrical device (for example, an electrical medical device such as a laryngoscope) which is reliably sealed against penetration by liquid and from which one or more batteries can be removed and replaced, and the seal reformed reliably without specialist sealing procedures being required.
Another known problem with battery powered electrical devices, including electrical medical devices such as laryngoscopes, is that the batteries may be depleted and the power supply may fail during use. The battery compartments of such devices will typically receive any of a wide range of batteries having a similar external shape but substantially different electrical properties and capacities. Furthermore, it may not be apparent if a battery has been used before. Thus, it may not be possible to predict exactly when the power supply may fail. Thus, in many known devices, there is a substantial risk of a failure in the power supply during use. This is of particular concern in relation to electrical medical devices, such as laryngoscopes, which may be used in emergency procedures. This risk of a failure in the power supply can be reduced by using new batteries for each procedure. However, this is very wasteful.
Accordingly, some aspects of the invention aim to provide improved methods of minimising the risk of the battery power supply of an electrical device failing during a procedure.